Stop-motion for knitting machines



Jan. 13, 1953 R. H. LAWSON STOP-MOTION FOR KNITTING MACHINES 4 Sheets-Sheet 1 Filed Jan. 22. 1952 L JNVENTOR.

I34 ROBERT H. LAWSON 6W x Amfij FlG.l.

ATTORNEYS Jan 13, 1953 R. H. LAWSON 25,

STOP-MOTION FOR KNITTING MACHINES Filed Jan. 22. 1952 4 Sheets-Sheet 2,

45 INVENTOR. FIG, 2 ROBERT H. LAWSON ATTORNEYS Jan. 13, 1953 R. H. LAWSON 2,625,026

STOP-MOTION FOR KNITTING MACHINES Filed Jan. 22. 1952 4 Sheets-Sheet 3 FIG.4.

I80 ,|B2 LISO' I 1 I am I92! I96 93 K I90 INVENTOR.

ROBERT H. LAWSON ATTORNEYS Jan. 13, 1953 R. H. LAWSON 2,625,026

STOP-MOTION FOR KNITTING MACHINES Filed Jan. 22. 1952 4 Sheets-Sheet 4 t 232 i K 226 T FIG. 5.

INVENTOR. ROBERT H. LAWSON BY w r M ATTORNEYS Patented Jan. 13, 19:53

I 2,625,026 STOP-MOTION roe KNITTING MACHINES Robert H. Lawson, Laconia, N. H., assignor to Scott & Williams, Incorporated, Laconia, N. H., a corporation of Massachusetts Application January 22, 1952, Serial No. 267,624

This invention relates to knitting machines and has particular reference to a stop motion provided in association with a take-up means involved in the production of stockings.

The type of machine to which the invention is generally applicable is one which knits stockings containing welts, the stockings being knit individually and separately and removed from the machine immediately after the knitting is completed. The type of machine just mentioned is disclosed in detail in my application Serial No. 207,075, filed January 22, 1951.

Individual separate stockings may be knit starting with bare needles in accordance withthe procedure and utilizing such instrumentalities as are disclosed in the patent to R. W. Scott No. 1,282,958, dated October 29, 1918. In accordance with this procedure, which need not be repeated herein in detail,.a non-ravelling selvage is first produced and thereupon loops are transferred to transfer elements which hold theinitial courses during the knitting of ahem or welt, there being produced. in the formation of this welt a sufficient number of courses to secure the desired length thereof. At the completion of the welt, the loops which were held bythe transfer elements are. returned to the needles and'knitting is resumed tying the .welt loops into loops. at the beginning of the eg so that a doubled or inturned welt is produced. .The welt fold as itis being formed and thereafter has generally been carried away from the needles to a considerable extent by gravity receiving. initial assistance from a presser such as shown in said Scott patent. The foregoing method has been quite satisfactory but it has been recognized that more uniform and perfect stitches might be formed if the fabric being knitted were made to fall away from the needles more readily and the welt prevented from twisting inside the needle cylinder. Furthermore, more satisfactory results would be obtained if the tension could be applied substantially throughout the following length of fabric.

When stockings are being produced in the form of a continuous string, tension may be applied to the fabric through the .use of take-up rolls which may be caused to stop or to advance at varying speeds as determined by control mechanism, thus to apply a uniform but variable tension tothe fabric. such as just indicated requires, however, that the stockings should be knit .in a continuous string joined, for example, by a yarn having sufficient strength for knitting and providing a'connection between successive stockings, but frail enough to The use of an arrangement 3 15 Claims. (01. 66-157) permit the various finished stockings to be torn apart or separated. However, if the stockings are to be knit separately so that each stocking is begun on bare needles, it will be evident that take-up rolls cannot be used.

Said prior application Ser. No. 207,075 discloses a method and means whereby during knitting proper tension may be applied to stockings when they are knit separately and individually. In particular, the invention is of importance as applied to the knitting of sheer ladies hosiery, for example on a 400 needle machine. In the case of sheer hosiery of this type the maintenance of proper tension during the knitting of the leg is particularly important. If the tension is not maintained uniform, there are likely to be produced shadow areas, streaks, or regions having the appearance of being scratched. If, on the other hand, a uniform tension is provided during knitting of the sheer leg fabric, these irregular-ities are avoided and stockings of acceptable appearance may be uniformly produced. In accordance With said application, therefore, tension is applied during the leg and foot knitting by the provision of a take-up device which grabs the welt of the stocking and pulls the leg and instep portions of the stocking uniformly downwardly under gravity action during the progress of the knitting. After the loopers rounds are completed the stocking is dropped from the needles, the take-up is released from the welt and the stocking may be blown by a blast of air transversely into a suitable receptacle. Simultaneously .the knitting of a subsequent stocking may be begun on bare needles as indicated above.

The present invention is concerned with a stop motion which is arranged to detect the proper removal of a stocking from the take-up. In the event that a completed stocking was not properly removed from the take-upv mechanism, it would be returned to the region adjacent to the needles and there caught by the needles or other knitting instrumentalities with resulting damage. The major advantage in the type of machine having a take-up of the type described is that it is highly automatic in the sense that a succession of stockings maybe begun, knit and removed automatically without attention on the part of a machine operator. With the take-up device of the type described a single operator may. be in charge of a large number of individual machines and will have no duty except that of taking care of failures and generally supervising the properma-. chine operations. these conditions it is particularly important to It will be evident that under.

provide an automatic stop motion for insuring the proper sequence of operations.

In accordance with the present invention, a blast of air is arranged to remove a completed stocking from the take-up after its mechanical release by the take-up. The stocking is directed by the air through a passage. In this passage there is located a detector, the detector being provided at a distance remote from the takeup approximately equal to the length of a stocking or somewhat greater. If the detector indicates the passage of a stocking at the proper time, there will then be assurance that the takeup mechanism has been cleared of the stocking so that it may properly proceed to position to seize a subsequent stocking. On the other hand, if the detector does not indicate the passage of a stocking at the proper time, the machine will be promptly stopped.

The invention also provides for resetting of the detector after the passage of a stocking and indication of such passage, and there is involved in accordance with the invention the provision of devices for stopping the machine in the event that the detector is not in condition to detect the passage of a stocking at the proper time, As will become more clearly evident hereafter the arrangements are such as to practically completely insure against the possibility that a stocking has not properly left the machine,

The general objects of the invention will be apparent from the foregoing and these as well as subsidiary objects particularly relating to details of construction and operation will become apparent from the following description read in conjunction with the accompanying drawings in which:

Figure 1 is an elevation, partly in section, of the upper portion of a knitting machine provided with a grab take-up and with the stop motion constituting the present invention, the take-up in this figure being shown in position for the reception of a welt;

Figure 2 is an elevation, partly in section, showing primarily the lower portion of the machine of Figure 1 and showing the grab take-up in the position which it assumes at the time of release of a stocking;

Figure 3 is a detailed elevation showing in particular the detector element and associated 4 parts of the improved stop motion;

Figure 4 is a transverse section showing the same, taken on the plane the trace of which is indicated at 4-4 in Figure 3; and

Figure 5 is a wiring and mechanical diagram illustrating in particular the electrical characteristics of the stop motion.

The figures show only those elements of a rotary cylinder knitting machine as are required for an understanding of the invention. It will, of course, be understood that this machine contains conventional elements well known to the art, and, in particular, reference may be made to said Scott patent for a more complete showing and description of those elements particularly concerned with welt formation. Reference may be made to my prior application Serial N0. 207,075 for details of construction of the grab take-up mechanism illustrated and described herein. As will be apparent hereafter, various features of the invention are applicable to machines of the stationary cylinder-rotary cam type, but for clarity and consistency of the description there will be hereafter referred to only a machine of the rotary cylinder type.

The needle cylinder illustrated at 2 is slotted to carry needles 4 with which cooperate conventional sinkers (not shown). A rotary dial 8 carries transfer elements [0 of the type described in said Scott patent. A stationary dial cap is provided with cams which in conventional fashion operate the transfer elements In. The dial 8 is provided with a series of openings [4 peripherally arranged so as to be brought during rotation successively in alignment with a tube which at proper times during operation receives air from the air connection 18 to direct a blast through the openings M, the blast being caused to be intermittent by reason of the interruptions afforded by the portions of the dial between the openings.

Relative movements of conventional character are imparted to the various instrumentalities in conventional fashion, and the particular driving means need not, therefore, be described.

As is usual in knitting machines of this general type, yarns are selectively fed from yarn fingers 20 under the control of push rods 22 moved in response to cams on the main cam drum of the machine.

There is frictionally held snugly within the conventional sinker ring of the machine a cylinder '24 having an outwardly flared upper edge to guide smoothly inwardly the portions of the fabric being knit, and particularly the fabric forming the welt. In the case of the present machine, this cylinder 24 is provided with a smooth interior and its lower edge is bevelled as indicated at 21 to provide a slight clearance for the grab take-up as will be hereafter described. The upper portion 29 of the interior of cylinder 24 is conically convergent downwardly to deflect the air inwardly of the cup.

A cylindrical cup 28 is carried by a bearing 30 mounted at the upper end of a tube 32 which passes slidably downwardly through openings in a carriage 34. A spring 38 is under compression and normally urges the sleeve 32 upwardly with respect to the carrier. Guide tracks 40 and 41 are embraced by the carrier, and in particular the carrier is provided with a sleeve 43 arranged to run on the track 4| which at its lower end is mounted in a bearing 45 carried by a foot member 42 which is suspended from a ring 41, fixed to the base of the machine, by rods 49. At their upper ends the guide tracks 40 and 4| are supported by reception in holes in ring 5| fixed to the upper end of cylinder raising tube 44 which is fixed against rotation but which is adapted for axial movements to produce through a ball-race arrangement and pins 52 axial movements of the needle cylinder for the purpose of adjusting the lengths of stitches drawn by the needles by producing relative movement between the needle cylinder and the needle actuating cams. These axial movements which are of slight extent are produced by engagement with a bracket 46 carried by cylinder raising tube 44 of the portion 48 of a lever acted upon by cams on the main cam drum of the machine.

As will appear hereafter the track member 4| is oscillated to a slight extent continuously during the knitting operation and by producing a disturbance causes the carriage 34 to drop more freely despite incidental friction of the tracks.

The tube 32 has fixed to it a member 54 which is held against rotation by the structural arrangement of the carriage 34. The end of a Bowden wire 58 is secured to the member 54 and runs through a sheath 60 which is secured to the carriage 34. The other end of the Bowden wire 58 is secured to a lever of conventional type (not shown) arranged to be acted upon by cams on the main cam drum. It may be remarked that through this Bowden wire the tube 32 may be drawn downwardly against the action of the spring 38 relatively to the carriage 34 and due to the flexibility of the Bowden wire there is no interference with this action because of the particular height at which the grab takeup may be located.

A rod 62 is secured at its lower end in the carriage 34 and extends upwardly through tube 32 supporting through aself-aligning ball bear ing (not shown) and/or a spring joint 65 (either or both of which provides a universal joint) a clamp member 65 which is arranged, as hereafter described, to clamp between its flange 68 and a shoulder of the cup 28 the edge of the welt of a stocking. The cup 2 8 is-provided with a series of openings indicated at 12 for-thedownward flow of air.

A cable 14v is secured to thecarriage'34 and is trained about pulleys (not shown) carried by a bracket secured to the'c'ylinder' raising tube 44 and thence extends to a winding drum 82 to which its end is fastened. The drum 82 is secured to a shaft 84 having bearings in a frame bracket and carrying a pinion 86 meshing with alarge gear 88 which has secured to it a ratchet 98 provided with teeth,- but with a tooth-missing in the region 92 so as to interrupt the advance of the ratchet by a pawl 94 which is pivoted to an arm 95 secured to a shaft 98 which is oscillated during operation of the machine through a link connection to the usual oscillating quadrant of the machine which is not shown. Pawl 94 is urged towards the ratchet by spring A lever I00 pivoted to the frame at I02 is provided with a pin I04 arranged to be acted upon by a cam I06 on the end of the main cam drum of the machine, this cam-having a cutaway portion at I06. A-pad member I08 formed on lever IE0 is arranged to engage the end of an adjustable screw I I0 carried by the upwardly extending arm of a lever IIZ' pivoted at II4 to the frame and normally urged counterclockwise, as viewed in Figure 1 by a strong spring H6. The lower arm of the lever H2 carries a follower roller II8 which rides onthe periphery of the cam I secured to the gear 88, cam I20-having a depression in its circumference at I22 which is somewhat greater in'angular extent than the diameter of roller H8.

The approximately horizontal arm I24 of lever I00 is connected by a link- I26 to a lever I28 pivoted at I30 to the'frame and arranged to act as a guard to lift pawl 94-out of operative relation with the ratchet 90. A-link- I32 connects the guard I28 at I34 to the lower end of a lever I35 pivoted at I38 to the frame and carrying a brake-shoe I40 which is adapted to engage the inner surface of the drum82. A light spring I42 connected between the upperend of lever I36 and a fixed pin on the frame urges the lever I35 counterclockwise as viewed 'in- Figure 1. A link I 44 is pivoted to the upperend of lever I36 and has a slot I46, in its other end which embraces a pin I48 secured to lever H2 and providing a connection p'ointfor a link I50 provided with a slot I52 embracing the pin I54 secured to lever Strand on-which-pinthere is pivoted the pawl 94-.- I a A bell crank I56 is adapted to be acted upon by a cam I58 on the main cam drum of the machine and is pivoted on the shaft 98 for rocking movement, its horizontally extending arm !60 being connected to a wire I62 (Figure 2) to control an air valve I 64 thereby to control the flow of air through a supply connection I66 to a nozzle I68 located: as indicated in Figure 2 and adapted to blow a finished stocking out of the machine. V

A cam follower lever indicated at I14 is arranged through' engagement by a suitable cam I12 on the main cam drum" to control the flow of air through the tube I8 by means of a conventional air valve which is not shown.

To a side bracket connected to the lever arm 36 there is connected a link 91 which through bell crank 99, a second link IN and an arm I03 connected to the upper end of track 4I serves to oscillate continuously-this track about its axis thereby producing a disturbance atthe bearing sleeve 43 which will tend to maintain the freedom of downwardmo vement of carriage 34 under its weight and the weight of its associated parts during its take-up action. As was previously pointed out the arm 96 oscillates continuously and hence so'does the track 4|.

Whereas in my prior application, Serial No. 207,075, a discharging nozzle was indicated as directing a finished stocking into a basket or other receptacle, in the present machine not onlyfor convenience but also for providing stop motion action there is provided in alignment with the nozzle I 66 and on the opposite side of the grab take-up. the open end I18 of an upwardlybent tube I16 which is secured to the machine frame and has its vertically'extending upper end I opening within a cylindrical receptacle I82, the upper end of which may be partially closed by a stretched piece of knitted material I84 having a central opening I86 and held in position at the rim of the receptacle by a band I88; As will be evident from what has just been described a stocking discharged from the grab take-up by the air blast will pass into and upwardly'through the tube I1 5, being finally located in the receptacle I82 where it-is trapped by the cover I84 but from which it may be readily removed 'bythe operator. To provide clear visibility of the stocking it is desirable to form the tube I16 and the receptacle I82 of transparent plastic which may also be used to form a sleeve I83 surround ing the grab take-up when in its lower position but provided with openings for the noz'zle'JBB and the lower end of tube I16.

The stop motion arrangement provided in accordance with the inventionlcompr'ises a detector I98 desirably in the form of a light blade of plastic material extending across the upper portion of tube I16 through slots-I9I in its'opposite walls. The detector blade ISIl'is' arranged edgeon with respect to the flower air through the tube I16 so that the air blast alone will not be sufficient to displace it upwardly; The detector I98 is desirably located at a distance from'the end I18 of. tube I16 greater than the length of a stocking knit by the machine though, if desired, the distance just mentioned may be somewhat less than a stocking length but with never-- theless quite reliable insurance of proper operation of the stop motion. There should, however, be substantial spacing so that except under unusual conditions the stocking will not reach the detector I90 before it is clear of the grab takeupinits releasing position--illustrated-in Fig ure 2.

The detector blade I90 is mounted on a pivot pin I92 and carries a cam member I94 provided with a high point I96 which is adapted to engage an operating lever I98 of a single-pole double-throw microswitch 200. The lever I98 moves between the full line position indicated at I98 and the dotted line position indicated at I98. These positions correspond respectively to the full line position I90 and the, construction line position I90 of the detector.

The cam I94 is provided with a laterally extending pin 202 which is arranged to be engaged, for resetting purposes, by the upper end of a lever 204 pivoted at 208 to the frame and urged clockwise by a spring 208 against the pull of a Bowden wire 2I0 which may move the lever 204 to an extreme position determined by an adjustable eccentric stop 2I2. The Bowden wire 2 I is connected to one arm of a lever 2 I4 pivoted on the shaft 98, the other arm 2I6 of this lever being arranged to be acted upon by a cam 2I8 on the main cam drum.

Referring now particularly to the diagram constituting Figure 5, the switch 200 is shown as having contacts 220 and 222 alternately engageable by a switch arm 238. Engagement of 238 with contact 220 corresponds to the full line position of detector I90. Engagement at contact 222 corresponds to the construction line position I90.

The contacts 220 and 222 are respectively connected to wiping blades 224 and 226 which are engageable by contact projections secured to the main cam drum of the machine. The physical arrangement of these will be obvious and only their electrical characteristics are indicated in Figure 5. The contact 224 is arranged to be engaged by a single contact member 230 carried by the drum which is electrically indicated as a conductor 234. The contact 226 is arranged to be engaged by two elements 228 and 232 carried by the drum which is electrically grounded as indicated at 236. As is shown in Figure 5, the order of contacts is first that of contact 226 with member 228, then contact of 224 with member 230 and then contact of 226 with member 232. This sequence will be hereafter more specifically referred to in connection with the operation.

The switch arm 238 is connected through a relay coil 240 to one terminal of the secondary of a step-down transformer 242 providing, for example 12 volts, safe for the proper operation of a stop motion. This same secondary terminal is connected to the coil 244 of a second relay. The coil of this second relay has its circuit completed through a contact 246 engaged, when coil 240 is not energized, with the armature 248 cf the first mentioned relay which is held in contact-making position by a spring 252. The armature 248 is grounded at 250.

The armature 254 of the relay comprising the coil 244 is pivoted at 256 intermediate its ends and is urged in a direction away from the coil by a spring 258 against the force of which however it may be held by the relay when the coil 244 is energized. The right-hand end of armature 254 as illustrated in Figure 5 is provided with an extension 260 engageable within the book forming the lower end of a lever 262 pivoted at 266 to v the machine frame. At its upper end the lever 262 is provided with a projection 268 arranged to engage an arm 210 mounted on a shaft 212 which arm is urged in a clockwise direction as viewed in Figure 5 by a strong spring 214 capable of overpowering the lighter spring 264. An arm 216 carried by the shaft 212 is connected by a rod 218 to the conventional mechanical stop motion of the machine, 1. e. to the mechanism which will release a connection in the drive pulley and/or stop a driving motor or otherwise effect stoppage of the machine. The end of the transformer secondary which is not connected to the relay coils is connected to a contact 280 which engages the lower end of lever 282 when the latter is in running position. Lever 282 is grounded as indicated at 292. When the stop motion is tripped as willhereafter appear, the electrical connection between contact 280 and the lever 262 is interrupted to open the secondary circuit of the transformer 242.

The operation of the machine independently of the stop motion will first be considered.

The operation may be best described by starting with the conditions which exist immediately following the discharge of a completed stocking from the machine into the receptacle. The Bowden wire running through sheath 60 will have been pulled to move downwardly tube 32 and cup 28 against the action of spring 38 to effect release of the stocking, the carriage 34 being in its lowermost position. The guard I28 will at this time be in its active position, i. e. swung clockwise from the position illustrated in Figure 1, preventing engagement of pawl 94 with the teeth of ratchet 90, this condition resulting from the position of pin I04 on the portion of cam I06 preceding the notch I06'. Under these conditions, the lever II2 will have been rocked by pad I08 clockwise so that roller II8 will be lifted beyond the periphery of cam I20 and pin I48 will have moved toward the right, relieving link I44 from the strong tension of spring II6. At the same time, because guard I28 is in its active clockwise position, link I32 will have pulled the lever I36 clockwise against the relatively light tension of spring I42 to release brake I completely from drum 82. It may be here noted that, at this time, the ratchet is not in the position bringing the toothless portion 92 under the pawl 94 but, in fact, a tooth is below this pawl so that if the pawl were released by the guard I28 racking would occur.

The makeup of the welt will start as soon as the finished stocking is discharged from the machine. The welt formation will start in the usual fashion with proper transfer, after several courses have been made, of loops to the transfer elements I0, all as described in said Scott patent.

The pin I04 will now drop into the notch I06 of cam I06. The result of this is to rock the guard I28 counterclockwise so that the pawl 94 which is continuously reciprocating may engage the teeth of ratchet 90. As lever I00 rocks counterclockwise, pad I08 will withdraw from the screw IIO but the movement of lever II2 under the action of spring I I6 will only be sufliclent to cause roller II8 to engage the periphery of cam I20, the notch I22 at this time not being in position to receive the pin. The result is that due to the slot at I 46 the link I 44 will not be pulled by the spring II6 to cause engagement of the brake shoe I48 under the action of this spring. The brake shoe nevertheless is engaged lightly with drum 82 through the action of spring I42 inasmuch as this spring may become effective due to the counterclockwise movement of the guard I28. The braking action is then such as to permit forcible movements to be applied to the drum but nevertheless such as to prevent the drum from 9 slipping under the weight of carriage 34 and its associated parts.

Pawl 94 now starts the racking of ratchet 90 raising the carriage 34 and its associated parts through the cable I4 against the frictional action of brake I40. It may be noted that due to the large ratio between gear 88 and pinion 84 a relatively few strokes of the pawl will raise the carriage 34 to its upper position. During the rise of the carriage, the knitting of the welt will continue but the rise will be completed before any substantial length of welt fabric is knitted. The upper air blast may be started to urge the welt loop into the rising cup 28.

As the carriage approaches the end of its rise the extensions of member 54 will engage the underside of a stationary ring 5I (Figure 1). The result is to arrest the upward movement of cup 28. The carriage 34, however, continues to move upwardly further compressing spring 38 and due to a slight advance of the main drum the Bowden wire in sheath 60 is released with the result that the grab take-up is more fully opened by movement of the cap 65 upwardly independently of the cup 28 and independently of any pull on the Bowden wire. When the cap 66 is just below the dial 8, the position indicated in Figure 1', the pawl 94 will have advanced the last tooth of the ratchet 93 before the toothless portion 92 and at the same time the roller IIB will have dropped into the notch I22 thus permitting lever II2 to move counterclockwise.

The situation generally described when the carriage is in its uppermost position may be further detailed as follows, inasmuch as an important efiect on the welt loop of fabric results therefrom.

As the pawl 94 advances it will drop into the hot-ch just below the toothless portion 92 of the ratchet and by engagement with the corresponding tooth it will advance the ratchet 90 to some extent counterclockwise. Just before pawl 94 enthe tooth, pin I54 will engage the rightend of slot I52 and link I50 will be moved to rock lever H2 lifting roller IIS and relieving from the tension of strong spring II6 the brake I40 which will remain under the tension of light spring I42. The result of this is to rotate correspondingly the cam I26, presenting below roller H8 the portion of this cam beyond notch I22. The result of this is that at the forward extreme of movement of pawl 94 the cap 66 will be raised to its highest position just short of the dial 8. As the pawl 94 now retracts spring 38, which will be substantially compressed during the forward pawl stroke, will force the carriage 34 and cap 66 downwardly since the cup 28 will be in a fixed upwardly arrested position by reason of engagement of member 54 with the underside of ring 5 I. The spring as is compressed sufficiently to move carriage 34 against the action of lightly applied brake I48 with the result that during this retraction of the pawl the cap 65 will be drawn downwardly, though not to closed position, there being simultaneously effected a corresponding counterclockwise rotation of drum 82 and clockwise rotation of gear 88, ratchet 90 and cam I20, the ratchet following the pawl in its retracting movenient.

However, as this action continues notch I22 will be brought beneath roller H8 and when pin I54 withdraws from the right hand end of slot I52 the roller H8 will drop into notch 522 thus releasing the lever H2 to reestablish action of strong spring H6 on lever I35 through link 144.

The brake shoe I40 is then forcefully applied against drum 82 preventing any further movement under the action of'spring 38. After this braking of the drum and the ratchet the pawl 94 may move still further to its fully retracted position in engagement with the toothless portion 92- of the ratchet. As will be evident so long as the. pin I04 is in the notch I06 the action. just described will reoccur upon each reciprocation of the pawl.

The result is that as the formation of the welt continues the cup- 28 will remain stationary from the standpoint of vertical movement but. the cap will have vertical strokes applied thereto between its uppermost position illustrated in Figure 1 and a somewhat lower-position short of closure on the cup 28. These vertical strokes by the cap 55 cause the periphery of cap 66 to stroke the fabric during its formation assisting proper entry of the fabric into the cup 28 in cooperation with the blasts of air from the tube I8 through the openings I4 with the res-ult'that 'thewelt will properly enter the cup. It willflbe noted that the air may pass freely through the openings 12- in the cup while the air cannot escape freely outside the cup between it and the sleeve 24. Figure 1 shows the condition of the welt just prior to the transfer of the held stitches from the transfer elements II) to the needles.

Simultaneously with the completion of the transfer the main cam drum advances and the pin I04 rises out of the notch I06 to the periphery of cam I05. Lever I00 is accordingly rocked clockwise, guard I28 is moved into position to cause pawl 94 to miss the ratchet teeth, and brake I40 is completely released from the drum. The spring 38 is accordingly free to move downwardly the carriage 34 to close the cap 66 on the cup 28, clamping the welt. It may be noted that the action actually occurs in steps, the strong spring I I6 being first rendered inoperative on the brake so that the spring 38 may act as previously described causing the cap to close on the cup against the lighter braking action of spring I42. Then finally the spring I42 is released as the guard I28 moves to its extreme clockwise position. While the spring I42 is applied the carriage assembly cannot drop of its own weight, but after brake I40 is released from the action of spring I42 the weight of the carriage is sufiicient to move the drum freely. The sequence just described insures that the welt loop will be clamped before dropping of the carriage assembly under its own weight can occur with the result that the clamping assembly will not drop away from the welt without clamping it.

With complete release of the brake the clamping assembly is free to drop as just indicated and accordingly as the knitting of the leg and other portions of the stocking takes place a uniform tension is applied by the assembly including the carriage 34 and other parts of the take-up. The upper air blast may be cut off after completion of the welt since it has no effect during the knit ting of the leg.

After the completion of the loopers rounds folfowing the toe the stocking is released from the needles and the lower air blast may become effective to drive the stocking out of the machine. For this purpose the lower blast is preferably started just after the stocking is complete and as it drops from the needles the Bowden wire in sheath is pulled to effect release of the welt The stocking accordingly is free to be blown 1at erally into and through the tube I10.

It will be noted that the clamp, when closed, is free to rotate with the stocking by reason of the bearings provided at 30 and at the top of rod 62 above joint 65. The self-aligning ball bearing or the spring joint 65 plays an extremely important part in the satisfactory operation of the invention due to the fact that it permits cap 66 to lean slightly in respect to cup 28 if necessary when clamping the welt fabric without in any way restricting the free rotation of the clamping unit. This is essential since the clamp is revolved simply by the tube of fabric suspended from, and turning with, the knitting needles. In the case of a stocking being knit of a fine denier nylon yarn the sheer fabric, if permitted to receive anything but the gentlest twist would at times cause wrinkles to form which could not be subsequently removed. Furthermore, twisting in itself will increase tension on the stitches being formed by producing an inward pull in addition to a vertical one. The method here employed therefore permits the fabric to revolve as a tube having substantially parallel and vertical sides. Generally speaking it will be essentially stationary during the reciprocatory knitting of heels and toes, the stocking twisting and untwisting slightly. In view of the fact that the entire circumference of the welt is gripped by the take-up there is uniform tension applied throughout the circumference of the leg and it has been found that sheer nylon stockings in particular are very free of the blemishes which commonly result due to slight variations in tension during knitting. Attention is drawn to the fact that the matching, clamping surfaces of cap 66 and cup 28 are extremely smooth, since any tendency toward roughness might prevent free entrance of the welt into the clamp or might damage the welt and/or prevent its free release when the clamp opened. Due to the smoothness of the clamping surfaces they are so shaped that when closed the gripped portion of the welt follows what is substantially a tortuous right angle path and is thus securely held.

What has been described is essentially the same as what occurs in the mechanism described in my application Serial No. 207,075, except that in the present machine the stocking is carried by the blast of air from nozzle I68 through the tube I16 into the receptacle I12.

There is a possibility that the stocking may be caught by the grab take-up so that even if this is opened for the discharge of the stocking it may fail to be carried into tube I'IB by the air blast. If this occurred, the completed stocking would be carried upwardly by the grab take-up, during its next rise, into the space below the dial where it would almost certainly be engaged by the needles or other elements resulting in jamming and damage to the machine elements. A major repair operation might then be necessary, though even if that was not required the completed stocking and probably the next one would be ruined. The object of the stop motion arrangement is to insure that the automatic cycle of operation will not proceed in the event that the stocking fails to pass through the tube I76.

Figure illustrates the electrical and mechanical elements of the stop motion in the conditions and positions corresponding to normal operation and in particular may be taken to represent the conditions existing prior to the completion of the toe of a stocking.

It is desirable to test the condition of the stop motion to determine whether the detect r I is in proper position extending across tube I16 as illustrated in Figure 3. In the move of the main cam drum prior to that which effects release of the stocking from the grab take-up the drum moves contact member 228 in contact with wiper 226. If detector I is in its proper position, it will be evident from Figure 5 that this electrical engagement will have no effect on the stop motion since the switch 200 is in such position that switch blade 238 will be in engagement with contact point 220 and out of engagement with contact point 222.

If, however, due to some maloperation the detector I90 is in the position I90, the switch blade 238 will be in contact with contact 222 so that energization of coil 240 would result as soon as contact takes place between 225 and 228. The result of this would be to move armature 248 downwardly breaking the circuit through relay coil 244 at 246 causing armature 254 to be rocked by spring 258 which will result in release of its end 260 from the hook of lever 262. If this occurs strong spring 214 will produce clockwise rocking of shaft 212 with concurrent counterclockwise rocking of lever 262, and the result will be stopping of the machine by movement of rod 218 and opening of the secondary circuit of transformer 242 at contact 280. The machine will accordingly stop before the drum move which would produce removal of the stocking from the grab take-up and release from the needles. The stopping of the machine will warn the operator that something is amiss and the operator may determine what is wrong, restarting the machine after moving the detector I90 to its proper active position.

Upon the occurrence of the move of the main cam drum which effects press-off of the stocking and opening of the valve I 84 to provide a blast or air, the stocking will normally be driven through the tube I16 into the receptacle I82, engaging the detector I90 and moving it to the position I90. The electrical effect of proper passage of the stocking will be to operate the switch 200 to move the contact blade 238 into engagement with contact 222. Since, on the last mentioned move, contact at 228 will be broken, the shift of switch 200 will be without effect. Immediately after this the next movement of the drum will cause engagement between wiper 224 and contact member 239. If the switch has been properly thrown as just described there will be no electrical result from this operation.

However, if the stocking has failed to move the detector I90 to the position ISO or if for some reason the stocking has passed into the receptacle but the detector I90 has failed to be moved or for some reason has redropped to the position illustrated in full lines in Figure 3, the result will be energization of relay 240 with re-- sultant stopping of the machine in the same fashion as previously described.

As pointed out above it is desirable that the detector I90 should be sufiiciently spaced from the grab-takeup that the detector I90 cannot be engaged and moved unless the stocking is free from the take-up.

Following the phase of the cycle just described, assuming that the machine continues to operate, or is manually restored to operation if the machine has been stopped due to the operation of the stop motion, the cam 2I8 will eifect pull on the Bowden wire 2| 9 so that the upper end of lever 204 by action on pin 202 will reestablish the proper position of detector I90 across tube I16.

At this time it is possible that the stocking may not have completely left the tube H6 and may be located in the upper end of this tube in position to prevent complete restoration of the detector to proper position, the detector possibly occupying a position after the Bowden wire 21s is released somewhere intermediate between its proper position at I90 and its extreme position I90. If this is the case the switch blade 238 will engage contact 222. In the next move of the drum following the attempted restoration of the detector to its proper position, wiper 225 will be engaged by the contact member 232. If the switch blade 233 is in the improper position engaging contact 222 the relay coil 2% will be energized resulting in stopping of the machine in the fashion previously detailed. The operator will thus have a Warning that something is amiss and may fully remove the stocking in case it prevents the proper location of the member Est. be here noted that the lever 2% only starts the movement of detector 198 towards its proper position, the movement being completed by the spring action of member I98 so that if a stocking is in the way of complete restoration of detector I90 the detector will not be forcibly moved to its proper position but may rest against the fabric of the stocking. If this occurs, while the machine will be stopped, the completed stocking will not be damaged by the detector and may be manually removed from the upper portion of tube I16.

From the foregoing it will be evident that the stop motion insures stoppage of the machine under substantially all abnormal and improper conditions which may arise. As a consequence there is provided such safeguard against damage as makes it possible to provide fully automatic operation without close attention on the part of an operator in charge of a large number of machines. In fact, unless a machine is stopped by the stop motion the operators only duty will be to empty completed stockings from time to time from the receptacle I82 of each of the machines under his care. It will, of course, be evident that an audible or visual signal may be provided in conjunction with the stop motion to give the operator immediate notice of stoppage of the machine.

However, while the foregoing is sometimes an advantage, precisely the opposite may be advantageous; i. e. the arrangement may be such that the operator will be obliged to pay close attention to the machine from the standpoint of removing and examining stockings as they are completed. Since a considerable amount of time and expensive yarn are consumed in the production of a sheer stocking, some mills require that each be inspected soon after completion in order that a possible knitting defect may be quickly detected and corrected. If this is desired, the receptacle [82 may be of such size as to hold only one stocking, and then, since another cannot enter it, the machine will stop until the operator removes the two stockings for inspection. In such case the operator would normally remove each stocking when completed to avoid stopping of the machine.

It will be evident that the tests for the condition of the detector may be made at various suitable times and in conjunction with various motions of the main cam drum and that various other changes may be made in the details of construction and operation of the stop motion It may without departing from the scope of the invention as defined in the following claims.

What is claimed is:

1. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically releasing the completed article from said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not released from said seizing means.

2. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed oil when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not so removed.

3. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not so removed, said stop motion device having an article detecting means located at a position remote, from said seizing means and in the path of removal of said article.

4. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed 01f when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, said removing means comprising a device for directing a blast of air against the article, and a stop motion device for stopping the machine in the event that a completed article is not so removed.

5. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, said removing means comprising a device for directing a blast of air against the article, a conduit through which the removed article is carried by the blast of air, and a stop motion device for stopping the machine in the event that a completed article is not so removed.

6. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, said removing means comprising a device for directing a blast of air against the article, a conduit through which the removed article is carried by the blast of air, and a stop motion device for stopping the machine in the event that a completed article is not so removed, said stop motion device having an article detecting means located in said conduit at a position remote from said seizing means.

7. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed ofi when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically releasing the completed article from said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not released from said seizing means, said stop motion device having an article detecting means movable by the article, and means for effecting stoppage of the machine if, at a predetermined time in the cycle of operation, said detecting means is in an abnormal position.

8. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically releasing the completed article from said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not released from said seizing means, said stop motion device having an article detecting means movable by the article, and means for effecting stoppage of the machine if, at a predetermined time in the cycle of operation, said detecting means is in a position in which it will not detect an article.

9. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically releasing the completed article from said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not released from said seizing means, said stop motion device having an article detecting means movable by the article, and means for effecting stoppage of the machine if, at a predetermined time in the cycle of operation, said detecting means is in a position in which it is abnormally held by an article.

10. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not so removed, said stop motion device having an article detecting means movable by the article, and means for eflecting stoppage of the machine if, at a predetermined time in the cycle of operation, said detecting means is in an abnormal position.

11. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not so removed, said stop motion device having an article detecting means movable by the article, and means for efiecting stoppage of the machine if, at a predetermined time in the cycle of operation, said detecting means is in a position in which it will not detect an article.

12. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, means for seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically removing the completed article from the vicinity of said seizing means, and a stop motion device for stopping the machine in the event that a completed article is not so removed, said stop motion device havingan article detecting means movable by the article, and means for efiecting stoppage of the machine if, at a predetermined time in the cycle of operation, said detecting means is in a position in which it is abnormally held by an article.

13. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed oil? when completed, means for automatically seizing the free end portion of each article and for imparting tension thereto during knitting subsequent to said seizure, means for automatically releasing the completed article from said seizing means, and a stop motion device for stopping the machine to prevent carriage of a completed article by said seizing means as it moves to seize a subsequent article.

14. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed off when completed, a receptacle of limited capacity for completed articles, a conduit opening to said receptacle and arranged to guide completed articles from the machine to the receptacle, means for producing discharge of completed articles from the machine through said conduit, and a stop motion device for stopping the machine in the event that a completed article fails to enter said receptacle.

15. A circular knitting machine comprising means adapted to knit separate articles each of which is pressed ofi when completed, a receptacle of limited capacity for completed articles, means for producing discharge of completed articles from the machine and into said receptacle, and a stop motion device for stopping themachine in the event that a completed article fails to enter said receptacle because of overloading of the receptacle.

ROBERT H. LAWSON.

N 0 references cited. 

